1. Field
The present invention relates to a laser radar system, and more particularly, to a laser radar apparatus for acquiring an image by using a laser radar light source having a variable pulse repetition rate, and a method of obtaining an image thereof.
2. Discussion of Related Art
A general laser radar system is utilized as an image sensor device for acquiring a 3-dimensional image of an object. The laser radar system is utilized in various fields, such as an industrial robot, a military robot, an autonomous robot, an autonomous vehicle, a structure diagnosis system, and a landslide monitoring system.
The laser radar system adopts a method of outputting light with laser, and receiving the output light and measuring the received light, not a method of acquiring an image from external light. Accordingly, the laser radar system may be used regardless of a surrounding environment, and output an excellent image. Accordingly, a laser light source is used in many fields.
The laser radar may confirm a distance to an object by radiating a laser light source to an object and measuring the light source returned from the object. The laser light source uses a pulse light source and a Continuous Wave (CW) light source. The pulse light source has excellent remote distance measurement performance, and resolution thereof has been improved to a centimeter (cm) level according to technology development. Accordingly, the pulse method is widely utilized to the laser radar system compared to the CW method. In an aspect of the light source, in the pulse method, heat is less generated in the light source compared to the CW method, and a peak output of a pulse may be made be very high, so that the pulse method is advantageous to measure a remote distance. In the case of the CW method, heat is generated in a light source unit in order to make a high output, and an intensity of an output is not high.
Accordingly, the laser radar using the pulse light source may acquire a 3D image by using the pulse light source. To this end, in order to improve efficiency of the laser radar, there is a method of adjusting an output of a pulse light source and adjusting a pulse width.
In this case, the laser radar adjusting an output of the pulse light source adjusts an output of the laser radar when measuring a short distance, so that there is an advantage in that a detector is prevented from being saturated, but has a disadvantage in that it is impossible to rapidly and precisely acquire an image of an object within a short distance.
Further, the laser radar adjusting the pulse width may improve resolution by decreasing a pulse width for an object positioned at a short distance, thereby accurately confirming a position. However, when the pulse width is decreased in the light source unit, there is a disadvantage in that an intensity of the peak of the laser light source may be increased, and the detector may be saturated. Further, the pulse width may be increased for an object positioned at a remote distance. However, when the pulse width is increased, there is a disadvantage in that the peak output of the pulse is decreased, and a signal does not proceed far.
Accordingly, there is necessity for a laser radar apparatus capable of acquiring an image regardless of a distance to an object by efficiently using a laser light source.